public class Rabbit {
    public int bornRabbit(int endMonth) {
        if (endMonth == 1) return 1;
        if (endMonth == 2) return 1;
        return bornRabbit(endMonth - 1) + bornRabbit(endMonth - 2);
    }

    public static void main(String[] args) {
        int endMonth = 12;
        System.out.println("rabbit end = " + new Rabbit().bornRabbit(endMonth));
    }
}
